/*
 * Rotocasting machine
 * Main program
 */

#include "U8glib.h" //library for OLED SSD1306 screen. Source : https://github.com/olikraus/u8glib

#define encoderPinA 11 //encoder pins
#define encoderPinB 12
#define pushPin 13

#define stepPin 6 // A4988 stepper driver pins
#define dirPin 5
#define enablePin 7

#define duration 180  // default duration
#define ymargin 10 //ymargin between two lines on OLED SSD1306 screen

unsigned short encoder = 0b000111; // encoder 6 bits state
unsigned short menu = 0; //current command
unsigned short in = 0; //inside a command 0 : no, 1: yes
unsigned short start = 0; //running 0: no, 1: yes
unsigned short rspeed[] = {20,80,150}; //motor speed {min,current,max}
unsigned int rtime[] = {1,duration,1200}; //elapsed time {min,current,max}
unsigned short rmode = 1; //acceleration mode 0:smooth, 1: medium, 2: sharp
unsigned long timer,next;
int d; //d : delay before stepper motor next step pulse
int r; //r: number of tenth milliseconds before next pulse
int i; //i: step number [0..200] on stepper motor


int screenWidth;
int fontHeight;

U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_NONE|U8G_I2C_OPT_DEV_0); //screen object

void writeTime() { //write elapsed time on second line screen
  int l;
  char stime[11];
  short pos = 0;
  if (rtime[1] >= 600) { //if elapsed time is more than 10 hours
    stime[pos++] = rtime[1] / 600 + '0'; // add tens digit
  }
  if (rtime[1] >= 60) { //if elapsed time is more than 1 hour
    stime[pos++] = (rtime[1] / 60) % 10 + '0'; // add units digit
    stime[pos++] =' ';
    stime[pos++] ='h';
    stime[pos++] =' ';
  }
  
  stime[pos++] = (rtime[1] % 60) / 10 + '0'; // add tens digit of minutes
  stime[pos++] = (rtime[1] % 60) % 10 + '0'; // add units digit of minutes
  stime[pos++] = ' ';
  stime[pos++] = 'm';
  stime[pos++] = 'n';
  stime[pos++] = 0;
  l = (screenWidth-u8g.getStrWidth(stime))/2; // calculate left margin to center text
  u8g.drawStr( l, 2*(fontHeight+ymargin), stime); //draw time
}

void writeMenu() { // write screen depending on menu value
  char com[16];
  int l;
 switch (menu) {
  case 0: // start/stop menu
    if (start) {
      strcpy(com,"STOP");
    } else {
      strcpy(com,"START");
    }
    l = (screenWidth-u8g.getStrWidth(com))/2;
    u8g.drawStr( l, fontHeight+ymargin, com);
    writeTime();
    break; 
  case 1: // speed menu
    strcpy(com,"SPEED");
    l = (screenWidth-u8g.getStrWidth(com))/2;
    if (in) {
      u8g.drawBox(0, ymargin +2, screenWidth, fontHeight);
      u8g.setDefaultBackgroundColor();
    }
    u8g.drawStr( l, fontHeight+ymargin, com);
    u8g.setDefaultForegroundColor();
    strcat(itoa(rspeed[1],com,10)," rpm");
    d = (screenWidth-u8g.getStrWidth(com))/2;
    u8g.drawStr( l, 2*(fontHeight+ymargin), com);
    break;
  case 2: // duration menu
    strcpy(com,"DURATION");
    l = (screenWidth-u8g.getStrWidth(com))/2;
    if (in) {
      u8g.drawBox(0, ymargin +2, screenWidth, fontHeight);
      u8g.setDefaultBackgroundColor();
    }
    u8g.drawStr( l, fontHeight+ymargin, com);
    u8g.setDefaultForegroundColor();
    writeTime();
    break;
  case 3: // mode menu
    strcpy(com,"MODE");
    d = (screenWidth-u8g.getStrWidth(com))/2;
    if (in) {
      u8g.drawBox(0, ymargin +2, screenWidth, fontHeight);
      u8g.setDefaultBackgroundColor();
    }
    u8g.drawStr( l, fontHeight+ymargin, com);
    u8g.setDefaultForegroundColor();
    switch (rmode) {
      case 0: 
        strcpy(com,"SMOOTH");
        break;
      case 1: 
        strcpy(com,"MEDIUM");
        break;
      case 2:
        strcpy(com,"SHARP");
        break;
    }
    l = (screenWidth-u8g.getStrWidth(com))/2;
    u8g.drawStr( l, 2*(fontHeight+ymargin), com);    
    break;
  }
}

void setup() { //program initialisation
  pinMode(encoderPinA, INPUT_PULLUP); //encoder pins are in input mode using pull up resistor
  pinMode(encoderPinB, INPUT_PULLUP);
  pinMode(pushPin, INPUT_PULLUP);
  pinMode(stepPin,OUTPUT); 
  pinMode(dirPin,OUTPUT); 
  digitalWrite(dirPin,HIGH); // set dir pin to clockwise rotation
  pinMode(enablePin,OUTPUT); 
  digitalWrite(enablePin,HIGH); // disable motor

  u8g.setFont(u8g_font_helvB14);
  fontHeight = u8g.getFontAscent()-u8g.getFontDescent();
  screenWidth = u8g.getWidth();

  u8g.firstPage(); //write start menu
  do {
    writeMenu();
  } while( u8g.nextPage() );

}

void loop() { //main loop
  unsigned short readPin = (unsigned short) digitalRead(encoderPinA); //read encoder pins
  encoder = (encoder & 0b110111) | (readPin << 3); //write encoderA state in the fourth digit

  readPin = (unsigned short) digitalRead(encoderPinB);
  encoder = (encoder & 0b101111) | (readPin << 4); //write encoderB state in the fifth digit

  readPin = (unsigned short) digitalRead(pushPin);
  encoder = (encoder & 0b011111) | (readPin << 5); //write push state in the sixth digit

  if (encoder == 0b110111) { //turn clockwise
    if (in) {
      switch (menu) {
        case 1: // increase speed
          if (rspeed[1] < rspeed[2]) {
            rspeed[1] += 10;
          }
          break;
        case 2: // increase time 30mn is time is more than 2 hours, 10mn if more than 10mn and 1mn else
          if (rtime[1] >= 120) {
            if (rtime[1] + 30 <= rtime[2]) {
              rtime[1] += 30 - rtime[1] % 30;
            } else {
              rtime[1] = rtime[2];
            }
          } else if (rtime[1] >= 10){
            rtime[1] += 10 - rtime[1] % 10;
          } else {
            rtime[1] +=1;
          }
          break;
        case 3: // increase mode
          if (rmode < 2) {
            rmode++;
          }
          break;
      }
    } else {
      menu = (menu + 1) % 4;
    }
    u8g.firstPage();  
  do {
    writeMenu();;
  } while( u8g.nextPage() );
  } else if (encoder == 0b101111) { //turn counterclockwise
    if (in) {
      switch (menu) {
        case 1: // decrease speed
          if (rspeed[1] > rspeed[0]) {
            rspeed[1] -= 10;
          }
          break;
        case 2: //decrease time
          if (rtime[1] > 120) {
            if (rtime[1] % 30) {
              rtime[1] -= rtime[1] % 30;
            } else {
              rtime[1] -= 30;
            }
          } else if (rtime[1] > 10) {
             if (rtime[1] % 10) {
              rtime[1] -= rtime[1] % 10;
             } else {
              rtime[1] -= 10 ;
            } 
          } else if (rtime[1] > rtime[0]) {
            rtime[1] -= 1 ;
          }
          break;
        case 3: // decrease mode
          if (rmode > 0) {
            rmode--;
          }
          break;
      }
    } else {
      menu = (menu + 3) % 4;
    }
    u8g.firstPage();  
    do {
      writeMenu();
    } while( u8g.nextPage() );
  } else if (encoder == 0b011111) { //push on encoder
    if (menu == 0) { // push on start/stop
      start = !start;
      if (start) {
        timer = millis();
        next = timer;
        r = 0;
        i = 0;
        digitalWrite(enablePin,LOW); // enable motor
      } else {
        digitalWrite(enablePin,HIGH); // disable motor
      }
    } else {
      in = !in;
    } 
    u8g.firstPage();  
    do {
      writeMenu();
    } while( u8g.nextPage() );
  }
  
  encoder = encoder >> 3; // write encoder current values to encoder previous values

  if (start) {
    if ((millis() -timer) > 60000UL) { // if one more minute is passed, rewrite time
      rtime[1] = rtime[1] - 1;
      timer += 60000UL;
      if (rtime[1] == 0) {  //end of time
        rtime[1] = duration;
        start = 0;
        digitalWrite(enablePin,HIGH); // disable motor
      }
      u8g.firstPage();  
      do {
        writeMenu();
      } while( u8g.nextPage() );
    }
    
    if (millis() > next) { // A4988 control
      digitalWrite(stepPin,HIGH); // send a pulse to step pin
      delayMicroseconds(500); 
      digitalWrite(stepPin,LOW);
      delayMicroseconds(500); 
      d = 3000 / rspeed[1]*(1+sin(0.031416*i)/(2*(3-rmode)));
      next += d / 10;
      r += d % 10;
      if (r >= 5) {
        r -= 10;
        next++;
      }
      i = (i+1) % 200;
    }    
  }
}